The two companies said as many as 100,000 terms will no longer produce search results; in addition, at the top of search results for more than 13,000 entries, warnings will appear making it clear that the associated content is illegal, pointing users towards websites where they can receive help. Auto-complete features, which predict child pornography search terms, will also be blocked.

The restrictions – which currently apply to English-speaking countries – will be rolled out in more than 150 languages in the next six months.

In an article in the Daily Mail, Google chief Eric Schmidt outlined his company's multi- pronged approach to “do everything in our power to protect children from harm.” Central strategies include:

Cleaning up search: “We've fine tuned Google Search to prevent links to child sexual abuse material from appearing in our results. While no algorithm is perfect – and Google cannot prevent pedophiles adding new images to the web – these changes have cleaned up the results for over 100,000 queries that might be related to the sexual abuse of kids.”

Detection and removal: “Pedophiles are increasingly filming their crimes...our engineers at YouTube have created a new technology to identify these videos. We're already testing it at Google, and in the new year we hope to make it available to other internet companies and child safety organizations.”

Technical expertise: “There are many organizations working to fight the sexual exploitation of kids online ...Google plans to second computer engineers to both the Internet Watch Foundation (IWF) here in Britain and the US National Center for Missing and Exploited Children (NCMEC).”